Fundamental ion-molecule reaction studies at elevated ion temperature and analytical application of an ion activation stage ('ion tunnel')

摘要

On the basis of the presented experimental and modeling results, a comprehensive thermal API chemistry for ionization methods operating in the gas phase (i.e. within the AP ion source) is proposed: Furthermore, the above scheme is expanded to non-thermal conditions encountered during ion transfer towards the collision free analyzer region as shown below: These findings clearly demonstrate the impact of the ion temperature on the ion chemistry prevailing in pressure regions which are collisionally dominated. Within the tunnel, collision rates of the order of at least 106 s-1 lead to significant ion activation, which not only shifts cluster equilibria but also drives bimolecular processes. The operation of an ion activation stage between capillary exit and the first sampling stage of API mass spectrometers may thus find several applications such as reagent ion preparation with carefully adjusted reactivity, controlled cluster decomposition, and even controlled covalent bond cleavage.